High levels of HDL cholesterol - often called "good" cholesterol - are associated with a reduced risk of coronary artery disease (CAD). It appears that HDL particles "scour" the walls of blood vessels, cleaning out excess cholesterol that otherwise might have been used to make the plaques that cause CAD. The HDL cholesterol is then carried to the liver, where it is processed into bile, and secreted into the intestines and out of the body. So, when we measure a person's HDL cholesterol level, we seem to be measuring how vigorously his or her blood vessels are being "scrubbed" free of cholesterol.
HDL levels below 40 mg/dL are associated with an increased risk of CAD, even in people whose total cholesterol and LDL cholesterol levels are normal. HDL levels between 40 and 60 mg/dL are considered "normal," and do not very much affect the risk of CAD one way or the other. However, HDL levels greater than 60 mg/dL are actually associated with a reduced risk of heart disease.
In recent years it has become apparent that it is a gross oversimplification to think of HDL cholesterol as always being "good." Some methods of increasing HDL levels, it turns out, do not reduce cardiac risk. Specifically, several randomized clinical trials with new drugs aimed at increasing HDL cholesterol have been a big disappointment. Indeed, when HDL was increased with some of these new drugs, the cardiac risk was increased instead of decreased. (Needless to say, these drugs were never approved by the FDA.) So the HDL story is more complex than scientists originally had hoped.
How can We Increase Our HDL Levels?Aerobic exercise. Many people don't like to hear it, but regular aerobic exercise (any exercise, such as walking, jogging or bike riding, that raises your heart rate for 20 to 30 minutes at a time) may be the most effective way to increase HDL levels. Recent evidence suggests that the duration of exercise, rather than the intensity, is the more important factor in raising HDL choleserol. But any aerobic exercise helps.
Lose weight. Obesity results not only in increased LDL cholesterol, but also in reduced HDL cholesterol. If you are overweight, reducing your weight should increase your HDL levels. This is especially important if your excess weight is stored in your abdominal area; your waist-to-hip ratio is particularly important in determining whether you ought to concentrate on weight loss.
Stop smoking. If you smoke, giving up tobacco will result in an increase in HDL levels. (This is the only advantage I can think of that smokers have over non-smokers -- it gives them something else to do that will raise their HDL.)
Cut out the trans fatty acids. Trans fatty acids are currently present in many of your favorite prepared foods -- anything in which the nutrition label reads "partially hydrogenated vegetable oils" -- so eliminating them from the diet is not a trivial task. But trans fatty acids not only increase LDL cholesterol levels, they also reduce HDL cholesterol levels. Removing them from your diet will almost certainly result in a measurable increase in HDL levels. Here's more about quick and easy review of transfats and the heart.
Alcohol. With apologies to the American Heart Association, which discourages doctors from telling their patients about the advantages of alcohol: one or two drinks per day can significantly increase HDL levels. More than one or two drinks per day, one hastens to add, can lead to substantial health problems including heart failure -- and there are individuals who will develop such problems even when limiting their alcohol intake to one or two drinks per day. Here's more on alcohol and the heart.
Increase the monounsaturated fats in your diet. Monounsaturated fats such as canola oil, avocado oil, or olive oil and in the fats found in peanut butter can increase HDL cholesterol levels without increasing the total cholesterol.
Add soluble fiber to your diet. Soluble fibers are found in oats, fruits, vegetables, and legumes, and result in both a reduction in LDL cholesterol and an increase HDL cholesterol. For best results, at least two servings a day should be used.
Other dietary means to increasing HDL. Cranberry juice has been shown to increase HDL levels. Fish and other foods containing omega-3 fatty acids can also increase HDL levels. In postmenopausal women (but not, apparently, in men or pre-menopausal women) calcium supplementation can increase HDL levels.
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